2026 Rankings

Least Reliable Water Systems in America — 2026

Last updated: June 4, 2026

42,670 ZIP codes ranked by Reliability Score #1: ZIP 03307 (Loudon, NH) — 10/100

Out of 42,670 ZIP codes with data across all 50 states, these are the lowest-ranked areas for reliability score. Each ZIP links to a full safety report with water quality, lead, radon, and flood data.

Statistic Value
ZIP codes ranked 42,670
Lowest value 10/100
Median value 70/100

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Reliability Score Safety Score
1 03307 Loudon NH 10/100 40/100
2 04664 Sullivan ME 10/100 33/100
3 04677 Sorrento ME 10/100 33/100
4 06241 Dayville CT 10/100 41/100
5 06258 Pomfret CT 10/100 50/100
6 06279 Willington CT 10/100 66/100
7 06331 Canterbury CT 10/100 66/100
8 10980 Stony Point NY 10/100 60/100
9 11202 Brooklyn NY 10/100 62/100
10 11240 Brooklyn NY 10/100 62/100
11 11241 Brooklyn NY 10/100 62/100
12 11242 Brooklyn NY 10/100 62/100
13 11243 Brooklyn NY 10/100 62/100
14 11244 Brooklyn NY 10/100 62/100
15 11245 Brooklyn NY 10/100 62/100
16 11247 Brooklyn NY 10/100 62/100
17 11248 Brooklyn NY 10/100 62/100
18 11251 Brooklyn NY 10/100 62/100
19 11252 Brooklyn NY 10/100 62/100
20 11254 Brooklyn NY 10/100 62/100
21 11256 Brooklyn NY 10/100 62/100
22 12430 Fleischmanns NY 10/100 41/100
23 23424 Rescue VA 10/100 70/100
24 25410 Bakerton WV 10/100 45/100
25 30807 Camak GA 10/100 66/100
26 48438 Goodrich MI 10/100 58/100
27 51540 Hastings IA 10/100 47/100
28 56253 Lake Lillian MN 10/100 45/100
29 59430 Denton MT 10/100 45/100
30 59542 Turner MT 10/100 22/100
31 67024 Cedar Vale KS 10/100 58/100
32 67066 Iuka KS 10/100 33/100
33 67478 Simpson KS 10/100 37/100
34 67575 Rush Center KS 10/100 45/100
35 67581 Sylvia KS 10/100 58/100
36 67585 Yoder KS 10/100 50/100
37 67657 Palco KS 10/100 3/100
38 67837 Copeland KS 10/100 33/100
39 67842 Ford KS 10/100 45/100
40 68324 Burr NE 10/100 33/100
41 68440 Steele City NE 10/100 24/100
42 68710 Allen NE 10/100 22/100
43 68865 Phillips NE 10/100 38/100
44 68935 Edgar NE 10/100 33/100
45 71247 Hodge LA 10/100 82/100
46 71432 Georgetown LA 10/100 65/100
47 73033 Eakly OK 10/100 55/100
48 73559 Mountain Park OK 10/100 70/100
49 74001 Avant OK 10/100 70/100
50 74422 Boynton OK 10/100 55/100
51 74636 Deer Creek OK 10/100 66/100
52 74637 Fairfax OK 10/100 70/100
53 74756 Sawyer OK 10/100 66/100
54 74837 Cromwell OK 10/100 66/100
55 76937 Eola TX 10/100 55/100
56 78369 Mirando City TX 10/100 70/100
57 78828 Barksdale TX 10/100 66/100
58 79227 Crowell TX 10/100 66/100
59 79255 Quitaque TX 10/100 55/100
60 79261 Turkey TX 10/100 55/100
61 79367 Smyer TX 10/100 39/100
62 79377 Welch TX 10/100 66/100
63 79380 Whitharral TX 10/100 39/100
64 79505 Benjamin TX 10/100 55/100
65 79713 Ackerly TX 10/100 72/100
66 79738 Gail TX 10/100 55/100
67 79785 Toyah TX 10/100 57/100
68 83633 King Hill ID 10/100 33/100
69 84317 Huntsville UT 10/100 43/100
70 85632 San Simon AZ 10/100 58/100
71 87560 Ribera NM 10/100 46/100
72 87569 Serafina NM 10/100 33/100
73 91903 Alpine CA 10/100 69/100
74 91931 Guatay CA 10/100 33/100
75 91963 Potrero CA 10/100 55/100
76 91990 Potrero CA 10/100 55/100
77 92365 Newberry Springs CA 10/100 50/100
78 93285 Wofford Heights CA 10/100 58/100
79 93643 North Fork CA 10/100 50/100
80 93644 Oakhurst CA 10/100 57/100
81 93669 Wishon CA 10/100 35/100
82 94570 Moraga CA 10/100 45/100
83 01921 Boxford MA 13/100 49/100
84 33114 Coral Gables FL 13/100 85/100
85 33446 Delray Beach FL 13/100 75/100
86 77413 Barker TX 13/100 90/100
87 79021 Cotton Center TX 13/100 54/100
88 92266 Palo Verde CA 13/100 80/100
89 02725 Somerset MA 15/100 42/100
90 02726 Somerset MA 15/100 37/100
91 02766 Norton MA 15/100 53/100
92 04414 Brownville ME 15/100 49/100
93 04863 Vinalhaven ME 15/100 58/100
94 06281 Woodstock CT 15/100 46/100
95 07828 Budd Lake NJ 15/100 50/100
96 08850 Milltown NJ 15/100 56/100
97 10504 Armonk NY 15/100 60/100
98 10506 Bedford NY 15/100 65/100
99 10507 Bedford Hills NY 15/100 65/100
100 10536 Katonah NY 15/100 65/100

Rankings by State

State ZIP Codes Ranked
Texas 2,728
California 2,674
New York 2,261
Pennsylvania 2,249
Florida 1,669
Illinois 1,610
Ohio 1,453
Virginia 1,273
Missouri 1,194
Michigan 1,179
North Carolina 1,132
Iowa 1,064
Minnesota 1,023
Kentucky 994
Georgia 987
Indiana 986
West Virginia 938
Wisconsin 902
Alabama 845
Louisiana 801
Tennessee 792
Oklahoma 774
New Jersey 769
Kansas 755
Massachusetts 742
Washington 732
Arkansas 711
Colorado 660
Maryland 630
Nebraska 625
South Carolina 565
Mississippi 564
Arizona 556
Maine 504
Oregon 483
Connecticut 442
New Mexico 429
North Dakota 413
Montana 408
South Dakota 397
Utah 350
Idaho 324
Vermont 312
District of Columbia 286
New Hampshire 284
Alaska 274
Nevada 254
Wyoming 195
Hawaii 141
Delaware 95
Rhode Island 93

Methodology

Water system reliability scores (0-100) combine violation frequency, violation recency, resolution rate, and system size. Systems with repeated health-based violations and unresolved issues score lowest. The reliability score focuses specifically on the water utility performance, distinct from the broader Home Safety Score.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-06-04.

Frequently Asked Questions

What does a low water reliability score mean?

A low reliability score (below 50) indicates a water system with frequent violations, poor resolution rates, or recurring compliance issues. These systems may have aging infrastructure, inadequate treatment, or management challenges.

How is reliability different from safety score?

The reliability score focuses specifically on the water utility performance (violations, resolution, compliance). The Home Safety Score is broader, also including lead risk, radon, and flood data. A ZIP code can have a reliable water system but still have high radon or flood risk.

Explore More Rankings

How this ranking is calculated, data sources, and limitations: Rankings Methodology →


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Disclaimer: Rankings are based on EPA, FEMA, and federal agency data. They reflect historical patterns and risk indicators, not necessarily current conditions. For the most current information, contact your local water utility or request a Consumer Confidence Report.

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